There's a book called "The Mood Cure" by Julia Ross and it talks a lot about diet and the importance of vegetables and protein in mental health. She tends to talk about depression, not bipolar, but has lot's of good info. She also recommends amino acids in pill form sold as vitamins that help with a number of difficulties with mood and anxiety. I tried them but didn't fell any different but I paid more attention to diet after I read it so it was a good read. Lot's of people seem to benefit from the amino acid therapy, like they say even 15 minutes after you take the pill. It sounds too good to be true and it was for me. But it may work better for other people.

Also, artificial sweeteners are supposed to affect mental health badly. My Pdoc didn't recommend diet drinks. I've read about this before but I forget the details.